Big Data is the large amount of data that cannot be processed by making use of traditional methods of data processing. Due to widespread usage of many computing devices such as smartphones, laptops, wearable computing devices; the data processing over the internet has exceeded more than the modern computers can handle. Due to this high growth rate, the term Big Data is envisaged. However, the fast growth rate of such large data generates numerous challenges, such as data inconsistency and incompleteness, scalability, timeliness, and security. This paper provides a brief introduction to the Big data technology and its importance in the contemporary world. This paper addresses various challenges and issues that need to be emphasized to present the full influence of big data. The tools used in Big data technology are also discussed in detail. This paper also discusses the characteristics of Big data and the platform used in Big Data i.e. Hadoop.